The tower should be more dirty.
The London smog of the early 1900s took it's toll on the bridge before it was cleaned shortly after the war.
The soot covered stone work made the white paint at the top stand out much more than it does today.
The current texture doesn't show the high tide line either.
Below the tide line the bridge was much cleaner because it was not exposed to the smog as much.
Finlay, the round towers at the corners stick out a little too much.
The railings are, indeed modern and should not be there.
For Comparison:
